1. Field of the Invention
The invention relates to a device and an operating method thereof, and more particularly, to a memory device and a programming method thereof.
2. Description of Related Art
A flash memory generally adopts the memory array of a NAND or a NOR architecture, wherein the NAND memory array is popular due to the suitability thereof in the application of high-density data storage. In general, a NAND memory array includes a plurality of memory cell strings, and each of the memory cell strings is electrically connected between a corresponding bit line and common source line. Moreover, the programming method of the NAND memory array usually includes programming a plurality of memory cells in a memory cell string from one side of the NAND memory array adjacent to a common source line along the direction toward a bit line one by one. Moreover, when the programmed memory cells are read, offset often occurs to the threshold voltage of the memory cells due to a back pattern effect. Therefore, current programming methods prevent an offset of the threshold voltage caused by the back pattern effect by changing the programming order of the memory cells. However, as the programming order of the memory cells is changed, the channel voltage of the memory cell string that does not need to be programmed may be blocked by memory cells having high threshold voltage and cannot be properly increased, thus causing program disturbance.